The present invention concerns a plug gauge and a measurement system for highly accurate pneumatic angle measurement.
In technical systems carrying a fluid flow, lines and/or bores with different, partly conical cross-sections are often to be found. Here the opening angle of the conical or cylindrical bore components are often functionally critical. Examples of this are the seat angle on a common rail injection nozzle or on GS high pressure injection valves.
Further examples are the feed or outlet bores in hydraulic pumps or switching valves.
It is particularly problematic here that to an increasing extent bores are no longer bound to be introduced by tools, i.e. by means of drills. Instead, methods such as laser drilling, grinding or moving erosion are used, with which the correct opening angle is no longer automatically guaranteed by the geometry of the tool. There is therefore an increasing need to check functionally critical opening angles very accurately with a tolerance of a few tenths of degrees.
For this purpose, mainly tactile systems are currently used, such as for example a Diatest double gauge according to the document DE 39 42 207 A1, or optical systems, such as for example a fiber optic interferometer according to the document DE 103 02 055 A1. Tactile systems can mechanically damage the workpiece to be checked and are relatively inaccurate. Optical systems require a lot of space and are very expensive; thus, a white light interferometer costs up to 200,000 ∈. The gravest disadvantage is, however, that the time required for the measurements is too long in order to be able to check each individual workpiece during mass production. The time available is only sufficient for sampling.